1. Field of the Invention
The present invention pertains to the art of vending machines and, more particularly, to a system for detecting a transfer of a selected product from one of a plurality of shelves to a product delivery device through movement imparted to a motor operatively connected to the product delivery device.
2. Discussion of the Prior Art
Vending machines for dispensing canned and/or bottled beverages have long been known. Early model vending machines release similarly sized bottles, one at a time, following deposit of a required purchase amount. In order to withdraw the selected product from the vending machine, the purchaser was required to, for example, manually remove a beverage container through a release mechanism on a shelf. Over time, manufacturers developed various mechanisms for releasing products from vending machines. The mechanisms range from a more conventional arrangement wherein products are guided to a chute, often times along a serpentine path, into a delivery port, to a more unique arrangement that shifts a transport carrier to a point adjacent a selected product, receives the selected product and then delivers the selected product to the adjacent delivery port.
Unlike the more conventional arrangements where the release and delivery of a product is readily determined, in the more unique arrangements, often times one or more cycles must be completed if a product is not properly released. If the product does not transfer into the transport carrier, there is nothing to deliver to the consumer. If the vending machine fails to deliver a product, the consumer is either refunded the purchase amount or the vending machine will initiate another vending cycle and make a second attempt to deliver the selected product. In either case, the vending cycle must typically near completion before the vending machine determines that the product has been delivered to the consumer. The time required to make this determination may lead to consumer frustration.
In order to address this problem, manufacturers have employed various sensors to determine whether a product has been properly transferred to a transport carrier. In accordance with one such arrangement, a sensor, such as an optical beam, is positioned in the transport carrier. When the selected product is transferred into the transport carrier, the beam is interrupted or broken. When the beam is broken, a signal is sent to a control indicating that a product is present in the transport carrier. While effective, occasionally the product does not enter the cup properly and the beam remains unbroken. In this case, the vending machine attempts to deliver a second product into the transport carrier or, if the product is sold out, ceases the vend operation and refunds the purchase amount, leaving the customer without the desired product.
Thus, despite the existence of product detection systems in the prior art, there still exists a need for a system that detects the receipt of a selected product in a vending machine product delivery device. More specifically, there exists a need for a product detection system that can reliably detect the presence of a product at an initial stage of a vending operation.